195 lines
6.5 KiB
C
195 lines
6.5 KiB
C
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/* Copyright (C) 2004 David Decotigny
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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USA.
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*/
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#ifndef _SOS_PAGING_H_
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#define _SOS_PAGING_H_
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/**
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* @file paging.h
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*
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* MMU management routines (arch-dependent). Setup the MMU without
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* identity-mapping physical<->virtual addresses over the whole
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* physical address space: a single, restricted and known, area is
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* identity-mapped, the remaining kernel/user space is not. To access
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* and manage the MMU translation tables (PD/PT on x86), we rely on a
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* particular configuration, called "mirroring", where the top-level
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* translation table (PD on x86) maps itself at a known and fixed (virtual)
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* address. The only assumption for this to be possible is that the
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* structure of the translation table entries are compatible at the
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* different levels of vadddr->paddr translation process (PDE and PTE
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* on x86 are Ok). Credits go to Christophe Avoinne for that.
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*/
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#include <sos/types.h>
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#include <sos/errno.h>
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/**
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* Basic SOS virtual memory organization
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*/
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/** Frontier between kernel and user space virtual addresses */
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#define SOS_PAGING_BASE_USER_ADDRESS (0x40000000) /* 1GB (must be 4MB-aligned) */
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#define SOS_PAGING_TOP_USER_ADDRESS (0xFFFFFFFF) /* 4GB - 1B */
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#define SOS_PAGING_USER_SPACE_SIZE (0xc0000000) /* 3GB */
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/** Length of the space reserved for the mirroring in the kernel
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virtual space */
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#define SOS_PAGING_MIRROR_SIZE (1 << 22) /* 1 PD = 1024 Page Tables = 4MB */
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/** Virtual address where the mirroring takes place */
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#define SOS_PAGING_MIRROR_VADDR \
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(SOS_PAGING_BASE_USER_ADDRESS - SOS_PAGING_MIRROR_SIZE)
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/**
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* sos_paging_map flags
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*/
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/** Usual virtual memory access rights */
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#define SOS_VM_MAP_PROT_NONE 0
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#define SOS_VM_MAP_PROT_READ (1<<0)
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#define SOS_VM_MAP_PROT_WRITE (1<<1)
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#define SOS_VM_MAP_PROT_EXEC (1<<2) /* Not supported on IA32 */
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/** Mapping a page may involve an physical page allocation (for a new
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PT), hence may potentially block */
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#define SOS_VM_MAP_ATOMIC (1<<31)
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/**
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* Setup initial page directory structure where the kernel is
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* identically-mapped, and the mirroring. This routine also
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* identity-maps the BIOS and video areas, to allow some debugging
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* text to be printed to the console. Finally, this routine installs
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* the whole configuration into the MMU.
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*/
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sos_ret_t sos_paging_subsystem_setup(sos_paddr_t identity_mapping_base,
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sos_paddr_t identity_mapping_top);
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/**
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* Map the given physical page at the given virtual address in the
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* current address space.
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*
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* @note *IMPORTANT*: The physical page ppage_paddr *MUST* have been
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* referenced by the caller through either a call to
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* sos_physmem_ref_physpage_new() or sos_physmem_ref_physpage_at(). It
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* would work if this were untrue, but this would be INCORRECT (it is
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* expected that one is owning the page before mapping it, or
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* otherwise the page could have been stolen by an interrupt or
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* another thread).
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*
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* @param ppage_paddr The address of a physical page (page-aligned)
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* @param vpage_vaddr The address of the virtual page (page-aligned)
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* @param is_user_page TRUE when the page is available from user space
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* @param flags A mask made of SOS_VM_* bits
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*
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* @note Unless the SOS_VM_MAP_ATOMIC bit is set in the flags, the
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* function may potentially block, because a physical page may be
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* allocated for a new PT.
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*/
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sos_ret_t sos_paging_map(sos_paddr_t ppage_paddr,
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sos_vaddr_t vpage_vaddr,
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sos_bool_t is_user_page,
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sos_ui32_t flags);
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/**
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* Undo the mapping from vaddr to the underlying physical page (if any)
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* @param vpage_vaddr The address of the virtual page (page-aligned)
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*
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* @return >= 0 when OK (the number of bytes of RAM unmapped), < 0 on error
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*/
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sos_ret_t sos_paging_unmap(sos_vaddr_t vpage_vaddr);
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/**
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* Undo the mapping from [vaddr .. vaddr + size[ to the underlying
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* physical pages (if any)
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* @param vpage_vaddr The address of the virtual page (page-aligned)
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* @param size The size (in bytes) to unmap. MUST be page-aligned
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*/
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sos_ret_t sos_paging_unmap_interval(sos_vaddr_t base_vpage_vaddr,
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sos_size_t size);
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/**
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* Return the page protection flags (SOS_VM_MAP_PROT_*) associated
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* with the address, or SOS_VM_MAP_PROT_NONE when page is not mapped
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*/
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sos_ui32_t sos_paging_get_prot(sos_vaddr_t vaddr);
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/**
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* Change the page access rights
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*/
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sos_ret_t sos_paging_set_prot(sos_vaddr_t vaddr,
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sos_ui32_t new_prot);
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/**
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* Change the access rights of the mapping from [vaddr .. vaddr +
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* size[ to the underlying physical pages (if any)
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* @param vpage_vaddr The address of the virtual page (page-aligned)
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* @param size The size (in bytes) to unmap. MUST be page-aligned
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*/
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sos_ret_t sos_paging_set_prot_of_interval(sos_vaddr_t vaddr,
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sos_size_t size,
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sos_ui32_t new_prot);
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/**
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* Return the physical address of the given virtual address. Since page
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* at physical addr 0 is not mapped, the NULL result means "page not
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* mapped".
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*/
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sos_paddr_t sos_paging_get_paddr(sos_vaddr_t vaddr);
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/**
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* Tell whether the address is physically mapped
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*/
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#define sos_paging_check_present(vaddr) \
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(sos_paging_get_paddr(vaddr) != NULL)
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/* *************************************************
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* Functions restricted to mm_context module
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*/
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/**
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* Release the references to all the referenced pages (and PT on
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* x86). On x86, this applies only to the USER pages and PT.
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*/
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sos_ret_t sos_paging_dispose(sos_vaddr_t vaddr_PD);
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/**
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* Copy the MMU configuration related to the kernel virtual area
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*/
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sos_ret_t sos_paging_copy_kernel_space(sos_vaddr_t dest_vaddr_PD,
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sos_vaddr_t src_vaddr_PD);
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/**
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* Retrieve the current physical address of the PD
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*/
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sos_paddr_t sos_paging_get_current_PD_paddr();
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/**
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* Change the current MMU configuration.
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*
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* @note DANGEROUS. Don't use it unless you know exactly what you're
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* doing !
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*/
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sos_ret_t sos_paging_set_current_PD_paddr(sos_paddr_t paddr_PD);
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#endif /* _SOS_PAGING_H_ */
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